Would to lock my PC.

Q : Would to lock my PC.

All user Password had Enter.
But not have Password box during open PC.
No windows to select admin or Guest.
But can entered during change the user ID
Which user will do. use windowsxp.

A : 

1. Start> Run and type control userpasswords2.

2. check out the "Users must enter a username and password to use this computer" issue (if any).

3. Click Apply.